The invention relates to a device for sorting flat objects comprising buckets into which the flat objects are loaded, each bucket being moved along a path above a collection of sorting outlets towards which the flat objects are removed.
The invention applies more specifically to a postal sorting machine. A postal sorting machine customarily consists of a single bucket conveyor, the buckets moving along a very long closed-loop path to serve a great many sorting outlets. To reduce the floor space occupied by such a machine, there has already been the idea of designing a number of horizontal levels on which the buckets move, these levels being connected to each other by a path portion of helical shape. However, this solution leads to problems with the tension of the chain that drives the movement of the buckets and the strains to which the chain is subjected are detrimental to the reliability of the machine. Furthermore, this solution entails very powerful conveyor drive which is expensive.
The object of the invention is to overcome this drawback.
To this end, the subject of the invention is a device for sorting flat objects comprising buckets into which the flat objects are loaded, each bucket being moved along a path above a collection of sorting outlets towards which the flat objects are removed, this device comprising at least one first conveyor consisting of buckets moving along a first path in a closed loop and a second conveyor, mechanically independent of the first conveyor, consisting of buckets moving along a second path in a closed loop superposed with the first path in a vertical direction, and being one wherein the movement of the buckets of the first conveyor along the first path and the movement of the buckets of the second conveyor along the second path are synchronized by an electric shaft and there is a zone along the two paths where the flat objects in the buckets of the second conveyor are transferred under gravity into the buckets of the first conveyor.
With this arrangement, the load that has to be motorized is lower than it is with a long conveyor, and this makes it possible to envisage a less powerful individual drive means for each conveyor. The reliability of the entire assembly is thereby improved because of the reduction in the lengths of chain, and the times taken to get the individual conveyors up to speed and the times taken to stop them can be shortened as far as possible, making it possible to improve the sorting rate.